Henri Bergson's philosophy presents the relationship between life and matter in both dualistic and monistic terms. Life is duration, a rhythm of incalculable novelty that approaches pure creative activity. In stark contrast, matter is identified with the determinism of homogeneous space. After Time and Free Will, Bergson concedes some share of duration to matter. In this context, his dualism can be understood as a methodological step towards the articulation of a monistic metaphysics of duration. This article suggests that the distinction between life and matter is also motivated by an unconscious imperative to establish a sexed hierarchy. Bergson repeatedly presents life as seminal, while matter is figured in terms of passivity